Ring roll mill

ABSTRACT

A ring roll mill for increasing the diameter of a ring shaped workpiece comprises an outer disc roll which is adapted to engage against the exterior periphery of the workpiece and a roll mandrel which is adapted to engage within the workpiece against the interior wall opposite to the outer disc roll. Each roll is mounted on a carriage which may be separately driven such as by a fluid pressure drive. A sensor roll is hydraulically biased against the periphery of the workpiece and it senses changes of diameter of the workpiece and effects movement of at least the carriage carrying the outer disc roll. The two rolls are advantageously mounted so that they move constantly away from the central axis of the ring by half the amount of the instantaneous increase of the ring diameter. The ring workpiece is advantageously supported on a plurality of angularly spaced, radially extending conical rollers. The workpiece is also advantageously engaged from respective opposite sides by fluid pressure biased centering rollers.

States Patent 1191 Wierege 1 51 Oct. 197a 1 1 lRllNG ROLL MILL [76] Inventor: Gustav Vieregge, Unterwaldener Str. 25, Dortmund-Wambel, Germany [221 Filed: May 7,1973

21 Appl.No.:357,778

[30] Foreign Application Priority Data May 9, 1972 Germany 2222608 {52] 11.5. CL... 72/10, 72/110 [51] Int. Cl. B2111 1/06 [58] Field 011' Search 72/10, 17,84, 105, 106, 72/107, 110; 29/1484 R [56] References Cited UNITED STATES PATENTS 3,186,202 6/1965 Ulrych 72/10 3,698,218 l0/l972 Wieting 72/10 3,709,011 1/1973 Wieting et al. 72/10 Primary Examiner- -Lowe1l A. Larson Attorney, Agent, or Firm--McGlew and Tuttle [5 7 ABSTRACT A ring roll mill for increasing the diameter of a ring shaped workpiece comprises an outer disc roll which is adapted to engage against the exterior periphery of the workpiece and a roll mandrel which is adapted to engage within the workpiece against the interior wall opposite to the outer disc roll. Each roll is mounted on a carriage which may be separately driven such as by a fluid pressure drive. A sensor roll is hydraulically biased against the periphery of the workpiece and it senses changes of diameter of the workpiece and effects movement of at least the carriage carrying the outer disc roll. The two rolls are advantageously mounted so that they move constantly away from the central axis of the ring by half the amount of the instantaneous increase of the ring diameter. The ring workpiece is advantageously supported on a plurality of angularly spaced, radially extending conical rollers. The workpiece is also advantageously engaged from respective opposite sides by fluid pressure biased centering rollers.

12 Claims, 2 Drawing Figures RING ROLL MILL BACKGROUND OF THE INVENTION 1. FIELD OF THE INVENTION This invention relates in general to the construction of a ring roll mill and, in particular, to a new and useful ring roll mill for increasing the diameter of ring shaped workpieces which includes an outer disc roll adapted to engage against the exterior periphery of the workpiece and an inner roll mandrel engageable against the inte rior of the ring opposite to the outer disc roll and wherein the increase in diameter of the ring shaped workpiece is effected by reducing the distance between the roll touching the inside of the ring and the roll touching the outside of the ring while the two rolls are guided for radial movement relative to the center of the ring.

2. DESCRIPTION OF THE PRIOR ART In the known ring roll mills, the material to be rolled is held stationary on one side by a'pair of radial rolls so that the center axis of the ring can migrate with increas ing ring diameter in the longitudinal direction of the rolling mill. The arrangement has the result that the necessary ring supports for the rings whose size and weight make the support on rollers necessary must be designed as supporting trucks which 'must be moved equally in the center of the axis of the ring. Another disadvantage is that adjustable ring boundaries for guiding the ring during the rolling process and/orfor calibrating the finished ring act on the ring either under a centering angle which varies greatly in dependence on the ring diameter and is thus of varying effectiveness, for example if limiting rollers are used which are arranged on stationary pivoted levers. Otherwise the means for moving the ring must be moved by means of a mechanically complicated system corresponding to the translatory movement of the circumferential points of the ring. In addition it is very difficult in ring roll mills having additional rolls which work on the end faces of the ring, particularly with thin ring walls, to control the movement and/or speed of these rolls so that the rolling process takes place without difficulty with the desired quality of the workpiece. The known embodiments of such ring roll mills were not fully satsifactory.

U.S. Pat. No. 2,132,370 describes a ring roll mill having a central axis of the ring which remains stationary during the rolling. This is achieved by employing a conical roll mandrel, which is equiped with several rolls of varying diameter and which bear on the entire inside diameter of the ring. The conical roll mandrel is moved vertically so that it widens the ring and it is passed against several radial rolls bearing on the outside diameter of the ringfSuch a rolling mill, however, permits only relatively minor diameter increases.

SUMMARY OF THE INVENTION In accordance with the present invention, there is provided a ring roll mill wherein the central ring axis remains stationary during the rolling and all the rolling mill parts which are required act on the end faces or the outside diameter of the ring. In the preferred arrange-' ment conical rolls are oriented in angularly spaced Iocations with their apices centered in respect to the center of the ring and they form ring supports; In'addition, the invention employs an outerdisc roller which bears against the exterior periphery of the workpiece and an inner roll mandrel which engages the interior wall opposite to the outer disc roll. The outer and inner rolls are mountedin a carriage which can be displaced in the radial direction of the ring and which will move constantly away from the central axis of the ring by half the amount of the instantaneous increase of diameter of the ring.

In a ring roll mill of the invention having a stationary central ring axis, all of the other rolling mill parts which are in contact with the ring to be rolled pass through simple translatory paths of motion because they can either be kept stationary or they can be moved on a recti linear path radially to the ring. The control of the carriages which carry the outer and inner rolls which bear against the respective outer and inner wall portions of the ring, can be effected by means of known sensors or feelers which engage the periphery of the workpiece and determine the ring. diameter or which may be employed to determine the ring diameter without actual contact therewith. In a proven embodiment, the displacement of the carriage is controlled by the movement of a scanning device, in the form of a feeler roll or a tactile feeler.

In known radial ring roll mills the support of the two rolls which engage the workpiece preferably are designed so that the roll touching the outside of the ring is mounted in a fixed position in the carriage and the roll touching the inside of the ring is displaceable in the carriage relative to the stationary roll. In order to effect the start of operation, the ring roll mill can be so designed that the carriage and the feeler can be displaced in synchronism relative to the ring and independently of each other and this synchronous movement can be lifted for the control of 'the carriage movement by the feeler. The lifting and restoration of the synchronous run of the carriage and the scanning device can be ef fected by the ring workpiece itself particularly by a signal generated by the ring on the scanning device.

There are no supporting trucks required for supporting the ring of the invention which must be displaced with increasing ring diameter. Instead a preferred embodiment of the ring roll mill according to the invention, provides that at least the two supporting rollers are rotatably but stationarily mounted in the mill frame and they preferably have the form of a truncated cone which lie with their cone apices on the center axis of the ring. This has the effect that the path speeds of the ring, which increase from the inside to the outside, in accordance with ring width, are identical with the speeds of those contacting circumferences of the sup porting rolls.

Frequently the rings must be rolled axially in order to achieve a given finished size. Four-rolling roll mills are known which include a pair of rolls acting on the two curved ring surfaces and which comprise a so-called disc roll and a roll mandrel that can be displaced relative to the latter, and in addition, a pair of conical rolls working on the end faces of the ring are provided. The conical rolls are displaced and controlled independence on the increase of the ring diameter so that it always acts on the end faces of the ring. In a ring roll mill, according to the invention, such a pair of conical rolls can also be provided additionally, where at least one roll is driven and the distance of the rolls from each other is variable. According to the invention the coni? cal rolls are radially indisplaceable with regard to the stationary central axis of the ring which is fixed by the positions of the carriage and the scanning device. and the cone apices of the rolls lie on the center axis of the ring. This has the effect that the path speed, which increases from the inside to the outside over the ring width is identical with the speed of the ring touching circumference of the conical rolls, so that a slip-free rolling is ensured, and the stationary position of the conical rolls in the rolling mill frame provides the additional advantage that the retaining, shifting and driving means can be much simpler. Preferably the feeler or sensor for the ring diameter is arranged in a known manner in the lane defined by the axes of the rolls touching the inside and the outside of the ring.

In ring roll mills centering rollers are usually provided to act on the ring circumference and which are mounted so that can be displaced independence on the increase of the ring diameter. Such centering rollers serve primarily to keep the ring in a position symmetrical to the longitudinal axis of the rolling mill. In the rolling mill of the invention, the centering rollers are arranged on the rolling mill frame and guides which permit a displacement of the rollers in a radial direction of the ring. The centering rollers bear constantly on the outside diameter of the ring so that they are moved by the ring radially to the outside upon diameter increase of the ring. A continuous biasing or restoring force is exerted on the centering rollers in order to prevent them from migrating laterally. Since the position of the centering rollers which bear on the outer ring circumference gives a measure of the increase of ring diameter, the position of the rollers can be used to provide a control for the displacement of the carriage carrying the radial rolls which act on the ring. In such a case, the centering rollers perform the function of a control feeler so that a separate additional feeler is not necessary. In one form therefore the centering rollers may be used to provide a control for displacing the carriages carrying the rolls which act on the mill cross-section. The centering rollers are advantageously provided with locking means so that the deflection of the roller can be set to a preselected maximum value and the circumferential surface of the centeringrollers can be profiled. This makes it possible to calibrate the rings which are being formed so that they accurately attain their final diameter during rolling and it is even possible to provide them with a profile.

Accordingly, it is an object of the invention to provide a ring roll mill for increasing the diameter of ring shaped workpieces which comprises an outer disc roll which is adapted to engage the exterior periphery of the ring shaped workpiece and an inner roll mandrel which engages the interior wall of the workpiece opposite to the outer disc roll and which includes means for supporting these rolls so that they may be moved relatively toward and away from the workpiece and which includes means for controlling the movement of the rollers during the formation of the workpiece.

A further object of the invention is to provide a ring roll mill which is simple in design, rugged in construction and economical to manufacture.

For an understanding of the principles of the invention,.reference is made to the following description of a typical embodiments thereof as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a top plan view of a roll mill constructed in accordance with the invention; and

FIG. 2 is a section taken along the line ll-ll of FIG.

GENERAL DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings in particular, the invention embodied therein comprises a ring roll mill for increasing the diameter of a ring shaped workpiece 7 which includes a first carriage 2 which rotatably supports a driven disc roll 3 having a shaft driven by a motor 3a. The carriage 2 is mounted in guides of a rolling mill frame I for displaceable movement toward and away from the ring shaped workpiece 7. First carriage movement means includes a fluid pressure driven motor 6 in the form of a cylinder 6a in which a piston 6b is movable. The piston 6b includes a piston rod 6c which is connected to the carriage 2 for displacing the carriage.

In accordance with the invention, a second roll or inner roll mandrel 5 is rotatably supported on a supporting frame 5a which is braced by a cross bar member 30 which is formed as an extension of the cylinder 6a. The inner roll mandrel 5 is advantageously mounted in removable end supports of the frame 5a in order to permit it to be inserted on the interior of the ring shaped workpiece 7. The roll mandrel 5 and the disc roll 3 are displaced relatively to either move them together toward the workpiece 7 or to move them in an opposite outward direction and the spacing between the disc roll 3 and the roll mandrel 5 varies during the rolling procedure.

In accordance with a further feature of the invention the ring is supported by a plurality of angularly spaced conical rolls 8 which are arranged around the center of the ring workpiece 7. The conical rolls 8 are rotated by separate drive motors as indicated schematically by the arrows 8a in FIG. 2. The rolls 8 are rotatably supported in the rolling mill frame 1 and their spaces lie on the center axis 9 of the ring workpiece 7.

The arrangement also includes a plurality of centering rollers 11 which are arranged around the periphery of the workpiece 7 and which are carried on piston rods;

Ha of a piston 11b which is slidable in a cylinder 12. The fluid pressure cylinder guides 12 permit a displacement of the rollers in the radial direction of the ring to accommodate for changes in diameter thereof. The displacement of the rollers 11 can be affected by an increase of the ring diameter or by a control exercise by directing fluid pressure to the fluid pressure cylinder 12.

In the embodiment indicated in addition to at least two opposite centering rollers l1, 11, there is provided a sensor roller or feeler roller 10 which bears on the outer circumference of the ring shaped workpiece 7. The roller 10 is advantageously arranged above a large diameter conical roll 8 and it comprises a measuring feeler which is carried on a piston rod 10a of a piston 10b which is movable in a control cylinder 13. Any change in movement of the piston 10b or variations of the pressure within the control cylinder 13 are sensed by a control 14 which includes means for selectively pressurizing fluid pressure control cylinders 4 and 4' to move pistons 4a to effect the displacement of the carriage 2 with the disc roll 3 relative to the inner roll mandrel 5.

During the rolling the ring diameter increases and the feeler roll moves to the right so that the carriage 2 with the rolls 3 and 5 move constantly away from the central axis 9 of the ring at a speed which is equivalent to half the amount of the instantaneous increase of the ring diameter and under the influence of the guidance control device 14. In addition to the large size conical roll 8 the ring shaped workpiece 7 is supported by the smaller diameter conical rollers which are rotatably mounted on the frame 1. In the embodiment shown, the

It would also be possible to arrange the conical rolls 8 on the ring circumference of the workpiece 7 so that their vertical plane of symmetry forms with the sectional plane II-Il an angle and preferably in such a way that with a clockwise rotation of the ring 7 when viewed in FIG. 1, the conical rolls 8 are radially immov able when turned upward and their cone apices are also in the central axis of the ring. Such a measure results in a selfcentering of the ring 7 so that the position of the ring is stabilized and the centering rollers 11 can be completely or partly removed. The conical rolls 8 act, for example on the same point of the ring circumference as the upper centering roller 11 shown in FIG. 1 and therefore could replace this roller.

While specific embodiments of the invention have been shown and described in detail to illustrate-the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

l. A ring roll mill for increasing the diameter of ring shaped workpieces, comprising an outer disc roll adapted to engage against the interior periphery of a ring shaped workpiece, a roll mandrel adapted to en gage against the interior wall of said ring shaped workpiece opposite to said outer disc roll, a first carriage rotatably supporting said outer disc roll, a second carriage rotatably supporting said inner roll mandrel, carriage movement means connected to said first and second carriages for shifting said outer disc roll and said inner roll mandrel relatively to shift them toward and away from each other and to shift them together to accommodate for changes in diameter of the workpiece, and sensor means adjacent the workpiece for sensing the diameter thereof and connected to said carriage movement means to displace said outer disc roll and said inner roll mandrel in a radial direction in respect to the workpiece ring and away from the central axis of the ring at a rate equal to half the amount of the instantaneous increase of the ring diameter during rolling.

2. A ring roll mill, according to claim 1, wherein said sensor comprises a roller engageable with the periphery of the ring shaped workpiece andis movable in accordance with the changes of the ring diameter.

3. A ring roll mill, according to claim 1, wherein said sensor means includes a relatively small roller engageable with the periphery of the ring shaped workpiece. and fluid pressure means supporting said roller and urging it against said workpiece and being responsive to outward movement of said roller to actuate said carriage movement means.

41. A ring roll mill, according to claim 1, wherein said first carriage is fixed and said second carriage carrying said inner roll mandrel is movable.

5. A ring roll mill, according to claim 1, including a plurality of centering rollers engaging the periphery of said ring, said sensor including a. feeler engaged with the ring to sense the outer ring diameter.

6. A ring roll mill, according to claim 1, wherein said carriage movement means includes a fluid pressure cylinder having a movable piston therein connected to said first-carriage for displacing said carriage toward and away from said ring shaped workpiece and said inner roll mandrel and a second fluid pressure operated piston cylinder having a second piston movable therein connected to said second carriage for displacing said inner roll mandrel therewith, said first and second carriages being interengaged and being guided for relative movement.

7. A ring roll mill, according to claim 1, including at least two supporting rollers arranged at angularly spaced locations below the ring shaped workpiece and upon which the end of the ring shaped workpiece is engaged, said supporting roller comprising truncated cones having apices at the central axis of said ring.

8. A ring roll mill, according to claim 1, including at least two conically shaped rollers acting on .the respective ends of said ring shaped workpieces at least one of which is rotatably driven and including a plurality of conical support rollers arranged in radial spaced relationship with their apices being located at the center of said ring shaped workpiece, said sensor including a roller engageable with the periphery of the workpiece at a location opposite to said inner roll mandrel.

9. A ring roll mill, according to claim 8, wherein said conical rolls acting on each end of said ring are arranged on each side of said sensor roll.

10. A ring roll mill, according to claim 1, including a plurality of centering rolls arranged around the pe riphery of the ring shaped workpiece in engagement therewith, each centering roll having a fluid piston connected thereto, a fluid pressure cylinder supporting said piston and guiding said piston, said centering rolls being displaceable in a radial direction.

11. A ring roll mill, according to claim 10, wherein said centering rolls comprise said sensor means.

12. A ring roll mill, according to claim 1, including a plurality of conical support rollers arranged below said ring and supporting said ring each having apices which intersect at the center of said ring, the plane defined by the vertical axes of said disc roll, said inner roll mandrel and the workpiece ring intersecting at the central axis of said ring. 

1. A ring roll mill for increasing the diameter of ring shaped workpieces, comprising an outer disc roll adapted to engage against the interior periphery of a ring shaped workpiece, a roll mandrel adapted to engage against the interior wall of said ring shaped workpiece opposite to said outer disc roll, a first carriage rotatably supporting said outer disc roll, a second carriage rotatably supporting said inner roll mandrel, carriage movement means connected to said first and second carriages for shifting said outer disc roll and said inner roll mandrel relatively to shift them toward and away from each other and to shift them together to accommodate for changes in diameter of the workpiece, and sensor means adjacent the workpiece for sensing the diameter thereof and connected to said carriage movement means to displace said outer disc roll and said inner roll mandrel in a radial direction in respect to the workpiece ring and away from the central axis of the ring at a rate equal to half the amount of the instantaneous increase of the ring diameter during rolling.
 2. A ring roll mill, according to claim 1, wherein said sensor comprises a roller engageable with the periphery of the ring shaped workpiece and is movable in accordance with the changes of the ring diameter.
 3. A ring roll mill, according to claim 1, wherein said sensor means includes a relatively small roller engageable with the periphery of the ring shaped workpiece, and fluid pressure means supporting said roller and urging it against said workpiece and being responsive to outward movement of said roller to actuate said carriage movement means.
 4. A ring roll mill, according to claim 1, wherein said first carriage is fixed and said second carriage carrying said inner roll mandrel is movable.
 5. A ring roll mill, according to claim 1, including a plurality of centering rollers engaging the periphery of said ring, said sensor including a feeler engaged with the ring to sense the outer ring diameter.
 6. A ring roll mill, according to claim 1, wherein said carriage movement means includes a fluid pressure cylinder having a movable piston therein connected to said first carriage for displacing said carriage toward and away from said ring shaped workpiece and said inner roll mandrel and a second fluid pressure operated piston cylinder having a second piston movable therein connected to said second carriage for displacing said inner roll mandrel therewith, said first and second carriages being interengaged and being guided for relative movement.
 7. A ring roll mill, according to claim 1, including at least two supporting rollers arranged at angularly spaced locations below the ring shaped workpiece and upon which the end of the ring shaped workpiece is engaged, said supporting roller comprising truncated cones having apices at the central axis of said ring.
 8. A ring roll mill, according to claim 1, including at least two conically shaped rollers acting on the respective ends of said ring shaped workpieces at least one of which is rotatably driven and including a plurality of conical support rollers arranged in radial spaced relationship with their apices being located at the center of said ring shaped workpiece, said sensor including a roller engageable with the periphery of the workpiece at a location opposite to said inner roll mandrel.
 9. A ring roll mill, according to claim 8, wherein said conical rolls acting on each end of said ring are arranged on each side of said sensor roll.
 10. A ring roll mill, according to claim 1, including a plurality of centering rolls arranged around the periphery of the ring shaped workpiece in engagement therewith, each centering roll having a fluid piston connected thereto, a fluid pressure cylinder supporting said piston and guiding said piston, said centering rolls being displaceable in a radial direction.
 11. A ring roll mill, according to claim 10, wherein said centering rolls comprise said sensor means.
 12. A ring roll mill, according to claim 1, including a plurality of conical support rollers arranged below said ring and supporting said ring each having apices which intersect at the center of said ring, the plane defined by the vertical axes of said disc roll, said inner roll mandrel and the workpiece ring intersecting at the central axis of said ring. 